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arjaystewart
Drywall over Plaster

I just bought a 1931 home with plaster in poor condition on the ceilings and walls of a 3rd floor, finished attic. Can I safely and durably apply 1/2" drywall directly over the plaster, and If so, what's the best method? The idea of removing the existing plaster, re-insulating and then putting up the drywall is daunting, to say the least.

havanagranite
Re: Drywall over Plaster

is this plaster on the old rock lathe (from the back side it would look like sheetrock with holes in it) or is it on the old wooden strips? you really don't want to just try to adhere the new rock to the plaster for the main reason that if the old plaster is coming loose it will simply come loose along with the new rock and both will be on the floor. usually what we do is to 3/4 frurring strips across the plaster going the opposite direction of the framing and fastening to the framing behind the plaster then hang the new rock to the furring strips. removing the old plaster is a serious job on that we surly agree. dirty dusty work that usually requires a jobsite dumpster on site but the finished product is worth it

Timothy Miller
Re: Drywall over Plaster

Howdy, i have similar home an yes installing 1/2 sheet rock to the existing plaster is common practice just be sure to use screws that are 3" long and spaced as normal practice. The huge draw back of removing the plaster is the dust is so fine the whole house and everything in it gets coated. if you pull the plaster you can leave or remove the lath. On a episode was how to install drywall, sheet rock, onto existing cracked failing plaster ceiling. Tom of TOH just screwed the rock onto the plaster....t

havanagranite
Re: Drywall over Plaster

what tim says would be fine as long as you are able to get your screws into the wood behind the plaster. and I will tell you when holding up a piece of drywall to the ceiling and trying to get a screw to go through hard old plaster and make sure you hit all the wood behind isn't that easy and you will wish you put up the furring strips it will make the hanging go much easier. and I wouldn't use screws that only go into the plaster you will pay for this decision on down the line. been doing this for too many years and seen to many people go wrong in this area. you pay for SHORT cuts in the LONG run. on ceilings using 1/2 inch rock your furring strips should be 16 inch on center.

plastrr385
Re: Drywall over Plaster

Find a good plasterer not a drywall finisher. We can fix most anything.:D

Hank Bauer
Re: Drywall over Plaster
plastrr385 wrote:

Find a good plasterer not a drywall finisher. We can fix most anything.:D

I agree with plastrr385.
Use Big Wally adhesive to reattach plaster to lath skim coat and it will be as good as new and last another 80 years.
How many drywall jobs have lasted longer than 80 years?

Timothy Miller
Re: Drywall over Plaster

Howdy, fellers you have my interest in repairing plaster ceilings . If it has cracked due to failure of the plaster globules that hold it up onto the lath, how without removing it or dry walling under it does one repair it? Moreover, other then the east part of USA i have not seen affordable plaster work. but readily affordable drywall. The cost and even locating a plasterer is a real paradox.

Hank Bauer
Re: Drywall over Plaster

To repair existing plaster over wood lath you may proceed as follows.
Read up on reattachment of plaster, Preservation Brief # 21
On page # 14 ( back page ) under reading list.
Phillips, Morgan. " Adhesives for the Reattachment of Loose plaster" A.P.T. Bulletin, Vol. X11,No 2 1980 pp.37-63
Now go to Big Wally's Adhesive, Inc.this material is the same as Phillips Morgan's only it is prepacked ( user Friendly )Follow instructions for adhesive don't require a plaster for this step.
Also if you have access to the upper side of the plaster I use the adesive and flood ( fill any voids )on the top side.
When all reattachment is completed find the best drywall finisher in your area say one that can produce a level 5 drywall finish with little to no sanding.
Than have him use a product called Master of Plaster restoration plaster base and finish.
mesh tape any cracks apply a base coat when dry apply second coat of base when dry apply the finish coat total combined thickness will not exceed 3/32 inch.Any good finisher or person that can use a trowel should be able to apply this product.
Maybe I should say have him make a sample on a piece of drywall to see how easy it can be applied and finished.
Have the finisher get a trowel that is used for Venetian Plaster
say one that is about 2 inches at the front and 3 inches at the back and no longer than about 6 inches ( trapezoid ) he will be able to apply more pressure with this making it smoother.

Timothy Miller
Re: Drywall over Plaster

Thanks for the additional information sounds like allot of work and cost how does it compare to simply installing the drywall instead?

Hank Bauer
Re: Drywall over Plaster
Timothy Miller wrote:

Thanks for the additional information sounds like allot of work and cost how does it compare to simply installing the drywall instead?

Don't know how plaster would compare to drywall.
The drywall people ran the plaster's out of the house about 60 years ago.
We ( plasters ) don;t like drywall people.

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